Don't try to apply query parameters if none were given

Sorry about the white space change, let me know if you want me to keep the trailing spaces in the future. At least there are 4 spaces this time.

Commit message --

Previously a query like 'SELECT 1 % 2' would result in an error saying
'incomplete format'. This fixes queries that use percent sign but have
no parameters but there's still additional work to be done, see Issue 11.